The present invention relates generally to a method and apparatus for stripping coating from a component, and more particularly to a method and apparatus for stripping coating from only a portion of a coated surface of a component.
Various methods are used to protect metal components exposed to high temperature environments. For instance, thermal barrier coatings are applied to surfaces of components exposed to high temperature environments to reduce the amount of heat which is transferred to the component. However, if the thermal barrier coatings are damaged (e.g., by field exposure or handling damage) the protection offered by the coatings may be compromised necessitating a repair. Typically, the coating is repaired by stripping the damaged coating and applying a new coating. This procedure is complicated by the presence of cooling holes in the component.
Although damaged thermal barrier coating can be repaired by conventional methods of stripping the damaged coating from the entire component and applying a new coating to the component, cooling holes must be masked before applying the new coating or they must be re-drilled (e.g., by laser drilling) after applying the new coating to ensure the holes are not blocked by the coating. These masking and/or re-drilling operations increase the cost of repairing damaged thermal barrier coatings. By reducing the amount of coating which is stripped, significant time and expense can be avoided by reducing the masking needed when the new coating is applied or by reducing the amount of re-drilling which may be required. Thus, there is a need for a method and apparatus for stripping coating from only a portion of a component.
Among the several features of the present invention may be noted the provision of a method of stripping coating from a portion of a coated surface of a component. The method comprises the step of fastening a mask sheet to the component over a region adjacent the portion of the coated surface. The mask sheet has a contour generally corresponding to a contour of the surface of the component. Further, the method includes the step of spraying a high pressure fluid jet from a spray head toward the portion of the coated surface after the mask sheet is fastened to the component to strip the coating from the portion of the surface. In addition, the method includes removing the mask sheet from the component after the coating is stripped from the portion of the surface.
In another aspect, the present invention includes an apparatus for masking a surface of a component to permit selective stripping of coating therefrom. The apparatus comprises a flexible sheet sized and shaped for positioning over a region of the surface of the component adjacent a portion of the coated surface to be stripped. The apparatus also includes a clamp for forming the flexible sheet to a contour generally corresponding to a contour of the surface of the component and for holding the sheet in position adjacent the surface of the component. Further, the apparatus includes a fastener for fastening the clamp to at least one of the surface of the component and the sheet.
Other features of the present invention will be in part apparent and in part pointed out hereinafter.